There is a gap between the head part, containing Antares, and the tail part, and some cultures see it as two constellations. In Navaho legend, the head is called First Big One and the tail is Rabbit Tracks.

In Skidi Pawnee legend, the head is a snake, and the tail is the important constellation of the Swimming Ducks: the rising of these in the morning was central to the calibration of their ceremonial calendar.

There were two versions of the Latin word for scorpion, scorpius and scorpio. The latter is still in use in some quarters as a so-called zodiac sign; it was the older word, the former being a re-formation after Greek skorpios.

I don't think it makes any sense to say where it is because I suspect that depends on where you are and also which way up you're standing.

Scorpius is the product of a forced mating between a male Scarran (reptilian and, from what we have seen of them, generally ruthless and unpleasant people) and a Sebacean (human-looking and not generally bad, although they make up the core of the thoroughly nasty Peacekeepers). The fact that scarrans are naturally hot creatures, while Sebaceans cannot tolerate heat, means that he spends all of his time in a cooling suit (resembling...well, think Catwoman with coattails, then add texture and armoured bits), with 'cooling rods' (glowsticks: red for hot, blue for cold, in a fit of imagination on someone's part) inserted into his brain. It also lent him his distinctive appearance - he resembles nothing so much as Nosferatu.

The mating was engineered by the Scarrans to see if anything useful could be derived from it. That they discovered, there was nothing; however, he concealed from them the fact that it did result in his ability to sense the energy signatures of creatures which, as well as being different in different species, 'changed when the speaker was not being entirely truthful'.

After several years of torture (Scorpius looks teenage when he escapes, but no figure is given and his appearance is such that it's difficult to tell) Scorpius managed to escape from the Scarran dreadnought on which he was imprisoned and ingratiate himself into the Peacekeepers, who, obsessed with racial purity (they are made up almost exclusively of sebaceans) would never normally have tolerated him, with information about Scarran technology and customs. It was between these times that he met Natira, had himself fitted with his brain-cooling device and adopted the name 'Scorpius'. Why an alien from the other side of the galaxy, who'd never heard of Earth until Crichton turned up, should have chosen to name himself after a constellation visible only from our fair planet I shall not speculate.

Scorpius' main aim has always been - or at least, so he claims - to achieve revenge on the Scarrans, and to this end he succeeded in gaining Peacekeeper support for his pet project: producing wormhole technology which will enable the Peacekeepers to gain the advantage over them. It was this that led to his role as persistent villain, since on discovering that John Crichton was unconsciously harbouring knowledge of said technology he began a relentless campaign to extract it from him, beginning with prolonged torture in the aurora chair, a device of his own invention whose purpose is to rip memories from the mind of the victim. Before Crichton escaped him, he also implanted in his brain a chip containing a replica of his own personality, the purpose of which was to search Crichton's brain for the knowledge he sought. He eventually removed the chip (although not before it had managed to, controlling Crichton's body, kill Aeryn, the fact that she got brought back to life notwithstanding), but the replica remained, beaten down and named Harvey by Crichton.

Scorpius left the Peacekeepers with what might have been a bang in something other than vacuum when, after Crichton engineered a faked deal in order to sabotage his wormhole project, previous villain Crais decided to be selfless and destroyed the command carrier on which it was housed in a suicide mission. He was then (or so we thought) betrayed by Braca to the truly vile Commandant Mele-On Grayza, and together they proceeded to torture him in his own chair, using a modified cooling rod (yellow glowstick) to...well, its main purpose seemed to be to enhance the torture experience and inhibit his motor control when he was being dragged around on a lead by Braca as a gesture of goodwill toward Crichton. In a further gesture, she proceeded to first shoot him and then bury him alive on a planet about to undergo a magnetic thingummy that would kill everything alive on the surface.

He survived. Unsurprising, considering he's been repeatedly blown up, shot and had his head melted and persistently refuses to die. He then, following in Crais's footsteps, rescued Aeryn from some as yet unspecified fate involving dying of heat delirium and took her back to Moya to use as a bargaining chip for asylum - which he, due to her overriding sense of honour, achieved.

Since that time, Scorpy has been residing on Moya, and gradually becoming, if not trusted, at least somewhat accepted by most of the crew. We do not yet know his exact purpose - according to him it is 'to safeguard John Crichton...among <conspiratorial eyebrows> other things'. He has, so far, removed the neural clone of himself from Crichton's mind (or, in other words, he killed Harvey! The utter, utter bastard killed Harvey!), made himself useful (and risked his life) to the extent of saving the lives of the crew at least once, and flirted outrageously with Sikozu. We have also discovered that, despite apparently having betrayed him to Commandant Cleavage, Lieutenant Braca is acting as a spy and agent for him within the Peacekeepers.

What? You read to the end? Nah. Nobody would spend that much of their precious life reading a ludicrously long writeup about a character in a televisionseries. Or writing one. Most certainly not.